Image data transmission system and image data transmission method

ABSTRACT

An image data transmission system and an image data transmission method are provided. The image data transmission system includes an image sensing device, a master device, and a serial transmission bus. The serial transmission bus electrically connects the image sensing device and the master device. The master device transmits a read command to the image sensing device through the serial transmission bus, and the image sensing device transmits a first data sequence to the master device through the serial transmission bus in response to the read command.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan applicationserial no. 107125354, filed on Jul. 23, 2018. The entirety of theabove-mentioned patent application is hereby incorporated by referenceherein and made a part of this specification.

BACKGROUND Technical Field

The invention relates to a data transmission technique, and particularlyrelates to an image data transmission system and an image datatransmission method.

Description of Related Art

Generally, an image sensor usually has parallel transmission pins forconnecting other devices through a parallel transmission bus. After theimage sensor completes an exposure operation and generates image data,the image sensor generally actively transmits the generated image datato the other device through the parallel transmission bus. Since thenumber of the parallel transmission pins is quite large, the cost ofhardware design is increased.

Moreover, the aforementioned other device may only passively wait toreceive the image data transmitted by the image sensor, and cannotdecide when to start the image data transmission. Therefore, theaforementioned other device has to be in a standby state waiting toreceive the image data at any time.

SUMMARY

The invention is directed to an image data transmission system and animage data transmission method, which are adapted to greatly reduce thenumber of pins of a transmission interface of an image sensor todecrease hardware cost of the image data transmission system, and let amaster device in the image data transmission system grasps a time pointat which the image sensor transmits image data.

The invention provides an image data transmission system. The image datatransmission system includes an image sensing device, a master device,and a serial transmission bus. The serial transmission bus electricallyconnects the image sensing device and the master device. The masterdevice transmits a read command to the image sensing device through theserial transmission bus, and the image sensing device transmits a firstdata sequence to the master device through the serial transmission busin response to the read command.

The invention provides an image data transmission method, which isadapted to an image data transmission system. The image datatransmission system includes an image sensing device, a master device,and a serial transmission bus. The image data transmission methodincludes following steps: transmitting a read command to the imagesensing device by the master device through the serial transmission bus;and transmitting a first data sequence to the master device by the imagesensing device through the serial transmission bus in response to theread command.

Based on the above, the image data transmission system and the imagedata transmission method adopt the serial transmission bus to serve as atransmission interface between the image sensing device and the masterdevice, so as to greatly reduce the number of pins of the image sensingdevice. Besides, the master device is adapted to actively send the readcommand to the image sensing device, so as to grasp a time point forimage data transmission.

To make the aforementioned more comprehensible, several embodimentsaccompanied with drawings are described in detail as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIG. 1A is a block schematic diagram of an image data transmissionsystem according to an embodiment of the invention.

FIG. 1B is a schematic diagram of signal transmission between a masterdevice and an image sensing device of FIG. 1A according to an embodimentof the invention.

FIG. 2 is a flowchart illustrating an image data transmission methodaccording to an embodiment of the invention.

FIG. 3 is a flowchart illustrating an image data transmission method ofthe master device of FIG. 1A according to an embodiment of theinvention.

FIG. 4 is a flowchart illustrating an image data transmission method ofthe master device of FIG. 1A according to another embodiment of theinvention.

FIG. 5A is a schematic diagram of a first data sequence of FIG. 4according to an embodiment of the invention.

FIG. 5B is a schematic diagram of the first data sequence of FIG. 4according to another embodiment of the invention.

FIG. 5C is a schematic diagram of the first data sequence of FIG. 4according to still another embodiment of the invention.

FIG. 6 is a schematic diagram of the first data sequence of FIG. 4according to still another embodiment of the invention.

FIG. 7 is a schematic diagram of the first data sequence of FIG. 4according to still another embodiment of the invention.

FIG. 8 is a schematic diagram of the first data sequence of FIG. 4according to still another embodiment of the invention.

FIG. 9 is a schematic diagram of the first data sequence of FIG. 4according to still another embodiment of the invention.

FIG. 10 is a flowchart illustrating an image data transmission method ofthe master device of FIG. 1A according to still another embodiment ofthe invention.

FIG. 11 is a block schematic diagram of an image data transmissionsystem according to another embodiment of the invention.

FIG. 12 is a flowchart illustrating an image data transmission method ofthe master device of FIG. 11 according to an embodiment of theinvention.

DESCRIPTION OF THE EMBODIMENTS

In order to fully convey the spirit of the invention, exemplaryembodiments are described in detail below with reference of theaccompanying drawings. It will be apparent to those skilled in the artthat various modifications and variations may be made to the structureof the present invention without departing from the scope or spirit ofthe invention after learning the exemplary embodiments of the invention.On the other hand, well-known components and steps are not described inthe embodiments to avoid unnecessary limitations to the invention.

An image data transmission system of the invention includes a masterdevice, an image sensing device and a serial transmission bus. Themaster device and the image sensing device performs image datatransmission there between through the serial transmission bus, wherethe image sensing device serves as a slave device of the master device.The image sensing device may perform exposure to generate image data.Only when the mater device transmits a read command to the image sensingdevice, the image sensing device transmits the image data to the masterdevice. In an embodiment of the invention, the master device mayactively transmit commands to the image sensing device to set exposurerelated parameters of the image sensing device and a start time pointwhen the image sensing device performs exposure, and instruct the imagesensing device to provide image data, etc., and the image sensing deviceserving as the slave device completely passively receives commands fromthe master device, and performs corresponding operations according tothe commands of the master device.

FIG. 1A is a block schematic diagram of an image data transmissionsystem according to an embodiment of the invention, and FIG. 1B is aschematic diagram of signal transmission between a master device and animage sensing device of FIG. 1A according to an embodiment of theinvention. Referring to FIG. 1A and FIG. 1B, the image data transmissionsystem 10 includes an image sensing device 1, a master device 2 and aserial transmission bus 3. The serial transmission bus 3 electricallyconnects the image sensing device 1 and the master device 2, and servesas a signal transmission interface between the image sensing device 1and the master device 2. In detail, the serial transmission bus 3 iscoupled to serial transmitting pins of the image sensing device 1 andserial transmitting pins of the master device 2. The master device 2 maytransmit a read command CMD_RD to the image sensing device 1 through theserial transmission bus 3, and the image sensing device 1 may transmit afirst data sequence DS_1 to the master device 2 through the serialtransmission bus 3 in response to the read command CMD_RD, where thefirst data sequence DS_1 includes image data.

In an embodiment of the invention, the image sensing device 1 is aCharge Coupled Device (CCD), a Complementary Metal-Oxide Semiconductor(CMOS) or other similar device or a combination of the above devices.The master device 2 may be a Central Processing Unit (CPU) or otherprogrammable general use or special use microprocessor, a Digital SignalProcessor (DSP), a programmable controller, an Application SpecificIntegrated Circuit (ASIC) or other similar device or a combination ofthe above devices. The serial transmission bus 3 may be a SerialPeripheral Interface (SPI) bus, an Inter-Integrated Circuit (I²C) bus, aSystem Management Bus (SMBus) or other similar serial bus.

FIG. 2 is a flowchart illustrating an image data transmission methodaccording to an embodiment of the invention, which is adapted to theimage data transmission system 10 of FIG. 1, though the invention is notlimited thereto. Referring to FIG. 1A, FIG. 1B and FIG. 2, the imagedata transmission method includes following steps. First, in step S002,the master device 2 transmits the read command CMD_RD to the imagesensing device 1 through the serial transmission bus 3. Then, the imagesensing device 1 transmits the first data sequence DS_1 to the masterdevice 2 through the serial transmission bus 3 in response to the readcommand CMD_RD, shown as a step S004 of FIG. 2.

In an embodiment of the invention, before the master device 2 transmitsthe read command CMD_RD to the image sensing device 1, the master device2 may first transmit a setting command CMD_SET to the image sensingdevice 1 through the serial transmission bus 3 to set exposure relatedparameters (for example, an exposure time, an aperture value, aluminance value, an ISO index, a correction constant, etc.) of the imagesensing device 1, though the invention is not limited thereto. Inanother embodiment of the invention, the aforementioned exposure relatedparameters may also be pre-stored in the image sensing device 1, so thatthe master device 2 may omit transmitting the setting command CMD_SET tothe image sensing device 1.

As described above, a start time point when the image sensing device 1performs exposure is determined by the master device 2. Therefore, themaster device 2 may transmit an exposure command CMD_EXP to the imagesensing device 1 through the serial transmission bus 3, and the imagesensing device 1 performs exposure to generate the image data inresponse to the exposure command CMD_EXP, though the invention is notlimited thereto.

When the master device 2 wants to read the image data generated by theimage sensing device 1, the master device 2 may transmit the readcommand CMD_RD to the image sensing device 1 through the serialtransmission bus 3. The image sensing device 1 may embed the image datain the first data sequence DS_1 in response to the read command CMD_RD,and transmit the first data sequence DS_1 to the master device 2 throughthe serial transmission bus 3. Since the data transmitted through theserial transmission bus 3 is data in a unit of bit, the first datasequence DS_1 is a data sequence in a unit of bit.

It should be noted that the setting command CMD_SET, the exposurecommand CMD_EXP and the read command CMD_RD transmitted by the masterdevice 2 are determined according to a type of the serial transmissionbus 3. For example, if the serial transmission bus 3 is implemented by aSPI bus, the setting command CMD_SET, the exposure command CMD_EXP andthe read command CMD_RD transmitted by the master device 2 are compiledin form of SPI instructions.

Since the image sensing device 1 still requires to perform a conversionoperation in order to obtain the integral image data and prepare thefirst data sequence DS_1 after executing exposure, a plurality ofembodiments are provided below to allow the master device 2 toeffectively determine whether the image sensing device 1 has preparedthe first data sequence DS_1.

In an embodiment of the invention, the image sensing device 1 mayprovide a state of the first data sequence DS_1 for the master device 2to inquire. Once the image sensing device 1 has obtained the image dataand prepared the first data sequence DS_1, the master device 2 may learnthat the first data sequence DS_1 has been prepared by inquiring thestate of the first data sequence DS_1, and then the master device 2 maytransmit the read command CMD_RD to the image sensing device 1 throughthe serial transmission bus 3. The prepared first data sequence DS_1 mayinclude an integral image frame or a plurality of image frames, and mayonly include a part of row images in one image frame, which isdetermined according to an actual application or design requirement.

FIG. 3 is a flowchart illustrating an image data transmission method ofthe master device 2 of FIG. 1A according to an embodiment of theinvention. Referring to FIG. 1A, FIG. 1B and FIG. 3, in step S101, themaster device 2 transmits the exposure command CMD_EXP to the imagesensing device 1 through the serial transmission bus 3, and the imagesensing device 1 performs exposure and generates the first data sequenceDS_1 in response to the exposure command CMD_EXP. In step S103, themaster device 2 transmits a check command to the image sensing device 1through the serial transmission bus 3, so as to detect a state of thefirst data sequence DS_1.

In an embodiment of the invention, the image sensing device 1 may have astorage (not shown), where the image sensing device 1 may store thestates of the first data sequence DS_1 in the storage by using differentcodes, and the master device 2 may determine whether the first datasequence DS_1 is ready by inquiring the code in the storage of the imagesensing device 1. For example, when the first data sequence DS_1 isready, the image sensing device 1 may write a first code into thestorage to represent that the first data sequence DS_1 is ready,otherwise, the image sensing device 1 may write a second code into thestorage to represent that the first data sequence DS_1 is not ready,where the first code and the second code are different. Therefore, themaster device 2 may read the content of the storage through the serialtransmission bus 3, and determine whether the first data sequence DS_1is ready according to the content of the storage. In an embodiment ofthe invention, the first code and the second code are, for example,different bit values.

In an embodiment of the invention, the aforementioned storage may be aregister, any type of static or dynamic Random Access Memory (RAM), aflash memory, a Hard Disk Drive (HDD), a Solid State Drive (SSD) or asimilar device or a combination of the above devices.

In another embodiment of the invention, when the image sensing device 1receives the check command transmitted by the master device 2 throughthe serial transmission bus 3, the image sensing device 1 may transmitthe state of the first data sequence DS_1 to the master device 2 throughthe serial transmission bus 3 in response to the check command.

Further, when the first data sequence DS_1 is ready, the image sensingdevice 1 sets the state of the first data sequence DS_1 to be valid,otherwise, the image sensing device 1 sets the state of the first datasequence DS_1 to be invalid. The master device 2 determines whether thestate of the first data sequence DS_1 is valid through inquiring, shownas a step S105. If the state of the first data sequence DS_1 is invalid,the flow returns to the step S103. If the state of the first datasequence DS_1 is valid, the master device 2 transmits the read commandCMD_RD to the image sensing device 1 through the serial transmission bus3, shown as a step S107.

When the image sensing device 1 receives the read command CMD_RDtransmitted by the master device 2, the image sensing device 1 outputsthe first data sequence DS_1 in response to the read command CMD_RD, andthe master device 2 may receive the first data sequence DS_1 through theserial transmission bus 3, shown as a step S109.

According to the above method, the master device 2 first checks whetherthe image sensing device 1 prepares the first data sequence DS_1, andthen transmits the read command CMD_RD to the image sensing device 1, inthis way, it is guaranteed that the image data in the first datasequence DS_1 received by the master device 2 is valid.

In another embodiment of the invention, the image sensing device 1 doesnot provide the state of the first data sequence DS_1 in advance, butembed the state of the first data sequence DS_1 in the first datasequence DS_1. The master device 2 may continuously transmit the readcommand CMD_RD to the image sensing device 1 through the serialtransmission bus 3 at any time. When the image sensing device 1transmits the first data sequence DS_1 to the master device 2 throughthe serial transmission bus 3 in response to the read command CMD_RD,the master device 2 may determine the state of the first data sequenceDS_1 only according to the received first data sequence DS_1.

FIG. 4 is a flowchart illustrating an image data transmission method ofthe master device 2 of FIG. 1A according to another embodiment of theinvention. Referring to FIG. 1A,

FIG. 1B and FIG. 4, in step S201, the master device 2 transmits theexposure command CMD_EXP to the image sensing device 1 through theserial transmission bus 3. The image sensing device 1 performs exposurein response to the exposure command CMD_EXP and generates the first datasequence DS_1.

In an embodiment of the invention, the first data sequence DS_1 includesan image data sequence and a first state sequence, where the first statesequence is used for representing a state of the image data sequence.When the image sensing device 1 generates the first data sequence DS_1,the image sensing device 1 additionally embeds the first state sequenceassociated with the state of the image data sequence into the first datasequence DS_1.

FIG. 5A is a schematic diagram of a first data sequence of FIG. 4according to an embodiment of the invention. Referring to FIG. 1A, FIG.4 and FIG. 5A. A first state sequence SS_1 a in the first data sequenceDS_1 includes header bits HD_1, HD_2, . . . , HD_L, and the image datasequence DS_IMG includes image bits P_1, P_2, . . . , P_N, where thefirst state sequence SS_1 a is configured in front of the image datasequence DS_IMG.

FIG. 5B is a schematic diagram of the first data sequence of FIG. 4according to another embodiment of the invention. Compared to theembodiment of FIG. 5A that the first state sequence SS_1 a is configuredin front of the image data sequence DS_IMG, the first state sequenceSS_1 a′ of FIG. 5B is configured behind the image data sequence DS_IMG,and the first state sequence SS_1 a′ of the first data sequence DS_1includes footer bits FT_1, FT_2, . . . , FT_M.

FIG. 5C is a schematic diagram of the first data sequence of FIG. 4according to still another embodiment of the invention. A differencebetween the first data sequence DS_1 of FIG. 5C and the first datasequence DS_1 of FIG. 5A is that the first data sequence DS_1 of FIG. 5Cfurther includes a first state sequence SS_1 a′, where the first statesequence SS_1 a′ is configured behind the image data sequence DS_IMG,and the first state sequence SS_1 a′ includes footer bits FT_1, FT_2, .. . , FT_M.

The master device 2 may determine whether the image data sequence DS_IMGis a valid image or invalid image according to at least one of the firststate sequence SS_1 a and the first state sequence SS_1 a′. Moreover,the exposure related parameters may also be set to at least one of thefirst state sequence SS_1 a and the first state sequence SS_1 a′. Itshould be noted that a data length (i.e. bit number) of the first statesequences SS_1 a, SS_1 a′ may be determined according to an actualapplication or design requirement of the image sensing device 1 and themaster device 2, as long as the master device 2 may interpret the firststate sequences SS_1 a, SS_1 a′.

Referring to FIG. 1A, FIG. 1B, FIG. 4 and FIG. 5A, in step S203, themaster device 2 transmits the read command CMD_RD to the image sensingdevice 1 through the serial transmission bus 3. When the image sensingdevice 1 receives the read command CMD_RD transmitted by the masterdevice 2, the image sensing device 1 outputs the first data sequenceDS_1 through the serial transmission bus 3 in response to the readcommand CMD_RD. In step S205, the master device 2 receives the firstdata sequence DS_1. In an embodiment of the invention, in the step S203,the master device 2 may continually transmit a plurality of readcommands CMD_RD to the image sensing device 1 through the serialtransmission bus 3.

In step S207, the master device 2 determines whether the state of theimage data sequence DS_IMG in the first data sequence DS_1 is validaccording to the first state sequence SS_1 a. If the state of the imagedata sequence DS_IMG in the first data sequence DS_1 is invalid, in stepS209, the master device 2 abandons the image data sequence DS_IMG in thefirst data sequence DS_1; if the state of the image data sequence DS_IMGin the first data sequence DS_1 is valid, in step S211, the masterdevice 2 retains the image data sequence DS_IMG in the first datasequence DS_1.

When the image sensing device 1 generates the first data sequence DS_1,the image sensing device 1 additionally embeds the aforementioned headerbits HD_1, HD_2, . . . , HD_L and/or the footer bits FT_1, FT_2, . . . ,FT_M in the first data sequence DS_1, and an advantage thereof is thatthe master device 2 may determine the state of the first data sequenceDS_1 according to the received first data sequence DS_1. However, suchmethod may increase a data amount of the first data sequence DS_1, andincrease a burden of image data transmission.

FIG. 6 is a schematic diagram of the first data sequence of FIG. 4according to still another embodiment of the invention. Referring toFIG. 1A, FIG. 1B, FIG. 4 and FIG. 6, the first data sequence DS_1includes the image data sequence DS_IMG, a first state sequence SS_1 band a first state sequence SS_1 b′. The image data sequence DS_IMGincludes image bits P_4, P_5, . . . , P_N−4, P_N−3, P_N−2. The firststate sequence SS_1 b includes 3 header bits HD_1, HD_2 and HD_3, andthe first state sequence SS_1 b′ includes 2 footer bits FT_1 and FT_2,where the 3 header bits HD_1, HD_2 and HD_3 sequentially substitute thefront 3 image bits P_1, P_2 and P_3 in the original image data sequence,and the 2 footer bits FT_1 and FT_2 sequentially substitute theposterior 2 image bits P_N−1, P_N in the original image data sequence.In this way, the data amount of the first data sequence DS_1 is equal tothe data amount of the original image data sequence. Moreover, a datalength (i.e. bit number) of the first state sequences SS_1 b, SS_1 b′may be determined according to an actual application or designrequirement of the image sensing device 1 and the master device 2, aslong as the master device 2 may interpret the first state sequences SS_1b, SS_1 b′.

When the master device 2 wants to process the image data sequenceDS_IMG, the master device 2 may replace the image bits P_1, P_2, P_3,P_N−1, P_N substituted by the header bits HD_1, HD_2 and HD_3 and thefooter bits FT_1 and FT_2 by black margins, or use an algorithm toprocess the image bits P_1, P_2, P_3, P_N−1, P_N substituted by theheader bits HD_1, HD_2 and HD_3 and the footer bits FT_1 and FT_2. Inthis way, not only almost complete image data is maintained, the dataamount of the first data sequence DS_1 may be maintained the same to thedata mount of the original data sequence.

When the image sensing device 1 does not prepare the first data sequenceDS_1 but receives the read command CMD_RD transmitted by the masterdevice 2, the image sensing device 1 transmits the first data sequenceDS_1 with the invalid image to the master device 2. Since a transmissionamount of the first data sequence DS_1 with the invalid image isprobably rather large, not only a considerable amount of transmissiontime is consumed, during the process of transmitting the first datasequence DS_1 with the invalid image, the subsequent first data sequenceDS_1 with the valid image probably has been prepared, but it is stillrequired to wait for transmission of the first data sequence DS_1 withthe invalid image before transmitting the subsequent first data sequenceDS_1. In order to save the time consumed for transmitting theaforementioned invalid image, in another embodiment of the invention,when the image sensing device 1 does not prepare the first data sequenceDS_1 but receives the read command CMD_RD transmitted by the masterdevice 2, the image sensing device 1 embeds a specific amount of dummydata in the data sequence. After the master device 2 receives the datasequence, the master device 2 may directly abandons the specific amountof dummy data.

FIG. 7 is a schematic diagram of the first data sequence of FIG. 4according to still another embodiment of the invention. Referring toFIG. 1A, FIG. 1B, FIG. 4 and FIG. 7. When the first data sequence DS_1is not ready, the image sensing device 1 transmits a second datasequence DS_2 to the master device 2 in response to the read commandCMD_RD. The second data sequence DS_2 includes a second state sequenceSS_2 c and a dummy data sequence DS_V, where the second state sequenceSS_2 c has a header bit HD_NG, and the dummy data sequence DS_V hasdummy bits DM_1, DM_2, . . . , DM_X, and the second state sequence SS_2c is used for representing that the dummy data sequence DS_V is invalid.

When the first data sequence DS_1 is ready, the image sensing device 1transmits the first data sequence DS_1 to the master device 2 inresponse to the read command CMD_RD. The first data sequence DS_1includes a first state sequence SS_1 c and an image data sequenceDS_IMG, where the first state sequence SS_1 c has a header bit HD_OK,and the image data sequence DS_IMG has image bits P_1, P_2, . . . , P_N,and the first state sequence SS_1 c is used for representing that theimage data sequence DS_IMG is valid.

In an embodiment of the invention, the image sensing device 1 may alwaysembed a fixed number of dummy bits DM_1, DM_2, . . . , DM_X in thesecond data sequence DS_2, for example, the image sensing device 1fixedly embeds 1024 dummy bits in the second data sequence DS_2. In thisway, the master device 2 may directly abandon the received fixed numberof dummy bits DM_1, DM_2, . . . , DM_X.

In another embodiment of the invention, the master device 2 may set theimage sensing device 1 to decide the number of the dummy bits DM_1,DM_2, . . . , DM_X embedded in the second data sequence DS_2 by theimage sensing device 1.

FIG. 8 is a schematic diagram of the first data sequence of FIG. 4according to still another embodiment of the invention. Referring toFIG. 1A, FIG. 1B, FIG. 4 and FIG. 8, when the first data sequence DS_1is not ready, the image sensing device 1 transmits the second datasequence DS_2 to the master device 2 in response to the read commandCMD_RD, so as to notify the master device 2 that the first data sequenceDS_1 is not ready, where the second data sequence DS_2 has at least onesecond state sequence SS_2 d, and each of the second state sequencesSS_2 d may be represented by a header bit HD_NG. When the master device2 receives the second data sequence DS_2, since the master device 2interprets that the second data sequence DS_2 has the header bit HD_NG,the master device 2 may directly skip the second data sequence DS_2 andcontinually interpret a next data sequence.

Comparatively, when the first data sequence DS_1 is ready, the imagesensing device 1 transmits the first data sequence DS_1 to the masterdevice 2 in response to the read command CMD_RD. The first data sequenceDS_1 includes a first state sequence SS_1 d and an image data sequenceDS_IMG, where the first state sequence SS_1 d has the header bit HD_OK,and the image data sequence DS_IMG has the image bits P_1, P_2, . . . ,P_N, and the first state sequence SS_1 d is used for representing thatthe image data sequence DS_IMG is valid.

After the image sensing device 1 performs exposure, the image sensingdevice 1 first generates a corresponding analog signal, and thenconverts the analog signal into a digital signal through anAnalog-Digital Converter (ADC), so as to generate the first datasequence DS_1. During the process of converting the analog signal intothe digital signal, if a pixel value of each pixel is recorded in 8bits, a pixel value of the strongest light is, for example, 00, and apixel value of the weakest light is, for example, FF. Generally, thepixel values of 00 and FF are hardly appeared on application of themaster device 2, so that the image sensing device 1 may set the pixelvalue of 00 or FF as a reserved value, or set the pixel value that isnot appeared on the application of the master device 2 or an insensitivevalue as the reserved value.

FIG. 9 is a schematic diagram of the first data sequence of FIG. 4according to still another embodiment of the invention. Referring toFIG. 1A, FIG. 1B, FIG. 4 and FIG. 9, when the first data sequence DS_1is not ready, the image sensing device 1 transmits the second datasequence DS_2 to the master device 2 in response to the read commandCMD_RD, so as to notify the master device 2 that the first data sequenceDS_1 is not ready, where the second data sequence DS_2 has at least onereserved value RS_FF.

When the first data sequence DS_1 is ready, the image sensing device 1transmits the first data sequence DS_1 to the master device 2 inresponse to the read command CMD_RD, where the first data sequence DS_1includes an image data sequence having the image bits P_1, P_2, . . . ,P_N.

In other words, the master device 2 may take the reserved value RS_FF asa feature value from a series of data sequences transmitted by the imagesensing device 1 through the serial transmission bus 3, and the firstdata sequence DS_1 entrained between the feature values has the validimage data. The master device 2 may directly abandon the second datasequence DS_2 having the reserved value RS_FF, and only retain imagedata other than the second data sequence DS_2 having the reserved valueRS_FF.

In still another embodiment of the invention, when the image sensingdevice 1 has prepared the first data sequence DS_1, the image sensingdevice 1 may notify the master device 2 that the first data sequenceDS_1 is ready by triggering an interrupt notification. FIG. 10 is aflowchart illustrating an image data transmission method of the masterdevice 2 of FIG. 1A according to still another embodiment of theinvention. Referring to FIG. 1A, FIG. 1B and FIG. 10, in step S301, themaster device 2 transmits the exposure command CMD_EXP to the imagesensing device 1 through the serial transmission bus 3, and the imagesensing device 1 performs exposure in response to the exposure commandCMD_EXP, and generates the first data sequence DS_1. When the first datasequence DS_1 is ready, the image sensing device 1 sets the state of thefirst data sequence DS_1 as valid, and the image sensing device 1transmits an interrupt signal to the master device 2 through the serialtransmission bus 3, so as to notify the master device 2 that the firstdata sequence DS_1 is ready.

When the master device 2 receives the interrupt signal transmitted bythe image sensing device 1 through the serial transmission bus 3, instep S303, the master device 2 transmits the read command CMD_RD to theimage sensing device 1 through the serial transmission bus 3 in responseto the interrupt signal. The image sensing device 1 transmits the firstdata sequence DS_1 to the master device 2 through the serialtransmission bus 3 in response to the read command CMD_RD. In step S305,the master device 2 receives the first data sequence DS_1.

FIG. 11 is a block schematic diagram of an image data transmissionsystem according to still another embodiment of the invention. FIG. 12is a flowchart illustrating an image data transmission method of themaster device 2 of FIG. 11 according to still another embodiment of theinvention. Referring to FIG. 1B, FIG. 11 and FIG. 12. In anotherembodiment of the invention, the image data transmission system 20includes an image sensing device 1, a master device 2 and a serialtransmission bus 3, where the image sensing device 1 includes adetermination pin 11, and the determination pin 11 is electricallyconnected to a detection pin 21 of the master device 2 through a wire 4.

In step S401, the master device 2 transmits the exposure command CMD_EXPto the image sensing device 1 through the serial transmission bus 3. Theimage sensing device 1 performs exposure in response to the exposurecommand CMD_EXP and generates the first data sequence DS_1. When thefirst data sequence DS_1 is ready, the image sensing device 1 sets thestate of the first data sequence DS_1 to be valid.

When the image sensing device 1 has prepared the first data sequenceDS_1, the image sensing device 1 drives a potential of the determinationpin 11 to a specific potential. In step S403, after the master device 2detects that the potential of the determination pin 11 is the specificpotential through the wire 4 and the detection pin 21, the master device2 transmits the read command CMD_RD to the image sensing device 1through the serial transmission bus 3. The image sensing device 1transmits the first data sequence DS_1 to the master device 2 throughthe serial transmission bus 3 in response to the read command CMD_RD. Instep S405, the master device 2 receives the first data sequence DS_1.

In another embodiment of the invention, the image sensing device 1 mayalso transmit the interrupt signal to the master device 2 through thedetermination pin 11 via the wire 4. Implementation detail of triggeringthe interruption may refer to related description of the embodiment ofFIG. 10, and detail thereof is not repeated.

In summary, since the image data transmission system and the image datatransmission method of the embodiments of the invention adopt the serialtransmitting interface, the number of pins of the image sensing deviceused for transmitting image data is greatly reduced. Moreover, themaster device is adapted to actively send the read command to the imagesensing device, so as to grasp a time point for image data transmission,and effectively determine whether the image data is valid.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the disclosed embodimentswithout departing from the scope or spirit of the invention. In view ofthe foregoing, it is intended that the invention covers modificationsand variations provided they fall within the scope of the followingclaims and their equivalents.

What is claimed is:
 1. An image data transmission system, comprising: animage sensing device; a master device; and a serial transmission bus,electrically connecting the image sensing device and the master device,wherein the master device transmits a read command to the image sensingdevice through the serial transmission bus, and the image sensing devicetransmits a first data sequence to the master device through the serialtransmission bus in response to the read command, wherein the first datasequence comprises: an image data sequence; and a first state sequence,configured to indicate whether the image data sequence is valid, whereinwhen the first data sequence is not ready, the image sensing devicetransmits a second data sequence including a preset number of dummy bitsto the master device in response to the read command, wherein the seconddata sequence further comprises a second state sequence configured torepresent that the preset number of dummy bits is invalid, and thepreset number of dummy bits is configured to be transmitted between thefirst state sequence and the second state sequence.
 2. The image datatransmission system as claimed in claim 1, wherein before the masterdevice transmits the read command to the image sensing device, themaster device transmits an exposure command to the image sensing devicethrough the serial transmission bus, and the image sensing deviceperforms exposure in response to the exposure command and generates thefirst data sequence.
 3. The image data transmission system as claimed inclaim 2, wherein the image sensing device comprises a storage, whereinwhen the first data sequence is ready, the image sensing device writes afirst code into the storage to represent that the first data sequence isready, otherwise, the image sensing device writes a second code into thestorage to represent that the first data sequence is not ready, whereinthe first code and the second code are different, wherein before themaster device transmits the read command to the image sensing device,the master device further reads content of the storage through theserial transmission bus, and determines whether the first data sequenceis ready according to the content of the storage.
 4. The image datatransmission system as claimed in claim 2, wherein before the masterdevice transmits the read command to the image sensing device, themaster device further transmits a check command to the image sensingdevice through the serial transmission bus, and the image sensing devicetransmits a state of the first data sequence to the master devicethrough the serial transmission bus in response to the check command,wherein when the master device checks that the state of the first datasequence is valid, the master device transmits the read command to theimage sensing device through the serial transmission bus, and otherwisethe master device again transmits the check command to the image sensingdevice.
 5. The image data transmission system as claimed in claim 2,wherein when the first data sequence is ready, the image sensing devicetransmits the first data sequence to the master device in response tothe read command, when the first data sequence is not ready, the imagesensing device continuously transmits a reserved value to the masterdevice in response to the read command.
 6. The image data transmissionsystem as claimed in claim 2, wherein when the first data sequence isready, the image sensing device transmits an interrupt signal to themaster device, and the master device transmits the read command to theimage sensing device in response to the interrupt signal.
 7. The imagedata transmission system as claimed in claim 2, wherein the imagesensing device comprises: a determination pin, electrically connected tothe master device, when the first data sequence is ready, the imagesensing device drives a potential of the determination pin to a specificpotential, and the master device transmits the read command to the imagesensing device after detecting that the potential of the determinationpin is the specific potential.
 8. The image data transmission system asclaimed in claim 1, wherein the first state sequence comprises at leastone of at least one header bit and at least one footer bit, wherein theat least one header bit is configured in front of the image datasequence, and the at least one footer bit is configured behind the imagedata sequence.
 9. The image data transmission system as claimed in claim1, wherein the first state sequence comprises at least one of at leastone header bit and at least one footer bit, wherein the at least oneheader bit is configured to substitute at least one bit in the front ofthe image data sequence, and the at least one footer bit is configuredto substitute at least one bit at posterior of the image data sequence.10. The image data transmission system as claimed in claim 1, whereinwhen the first data sequence is ready, the first state sequence isconfigured to represent that the image data sequence is valid, and theimage sensing device transmits the first data sequence to the masterdevice in response to the read command.
 11. The image data transmissionsystem as claimed in claim 10, wherein when the first data sequence isnot ready, the image sensing device transmits the second state sequenceto the master device in response to the read command, so as to notifythe master device that the first data sequence is not ready.
 12. Animage data transmission method, comprising: transmitting a read commandto an image sensing device by a master device through a serialtransmission bus; transmitting a first data sequence to the masterdevice by the image sensing device through the serial transmission busin response to the read command, wherein the first data sequencecomprises an image data sequence and a first state sequence, and thefirst state sequence is configured to indicate whether the image datasequence is valid; and when the first data sequence is not ready,transmitting a second data sequence including a preset number of dummybits to the master device by the image sensing device in response to theread command, wherein the second data sequence further comprises asecond state sequence configured to represent that the preset number ofdummy bits is invalid, wherein the preset number of dummy bits isconfigured to be transmitted between the first state sequence and thesecond state sequence.
 13. The image data transmission method as claimedin claim 12, further comprising: before transmitting the read command tothe image sensing device by the master device, transmitting an exposurecommand to the image sensing device by the master device through theserial transmission bus, such that the image sensing device performsexposure in response to the exposure command and generates the firstdata sequence.
 14. The image data transmission method as claimed inclaim 13, further comprising: when the first data sequence is ready,writing a first code into a storage of the image sensing device by theimage sensing device to represent that the first data sequence is ready,otherwise, writing a second code into the storage by the image sensingdevice to represent that the first data sequence is not ready, whereinthe first code and the second code are different; and beforetransmitting the read command to the image sensing device by the masterdevice, further reading content of the storage by the master devicethrough the serial transmission bus, and determining whether the firstdata sequence is ready according to the content of the storage.
 15. Theimage data transmission method as claimed in claim 13, furthercomprising: before transmitting the read command to the image sensingdevice by the master device, further transmitting a check command to theimage sensing device by the master device through the serialtransmission bus, such that the image sensing device transmits a stateof the first data sequence to the master device through the serialtransmission bus in response to the check command, wherein when themaster device checks that the state of the first data sequence is valid,the master device transmits the read command to the image sensing devicethrough the serial transmission bus, and otherwise the master deviceagain transmits the check command to the image sensing device.
 16. Theimage data transmission method as claimed in claim 13, furthercomprises: determining whether the image data sequence is valid by themaster device according to the first state sequence.
 17. The image datatransmission method as claimed in claim 16, wherein the first statesequence comprises at least one of at least one header bit and at leastone footer bit, wherein the at least one header bit is configured infront of the image data sequence, and the at least one footer bit isconfigured behind the image data sequence.
 18. The image datatransmission method as claimed in claim 16, wherein the first statesequence comprises at least one of at least one header bit and at leastone footer bit, wherein the at least one header bit is configured tosubstitute at least one bit in the front of the image data sequence, andthe at least one footer bit is configured to substitute at least one bitat posterior of the image data sequence.
 19. The image data transmissionmethod as claimed in claim 16, further comprising: when the first datasequence is ready, the first state sequence is configured to representthat the image data sequence is valid; and transmitting the first datasequence to the master device by the image sensing device in response tothe read command.
 20. The image data transmission method as claimed inclaim 19, further comprising: when the first data sequence is not ready,transmitting the second state sequence to the master device by the imagesensing device in response to the read command, so as to notify themaster device that the first data sequence is not ready.
 21. The imagedata transmission method as claimed in claim 13, further comprising:when the first data sequence is ready, transmitting the first datasequence to the master device by the image sensing device in response tothe read command; and when the first data sequence is not ready,continuously transmitting a reserved value to the master device by theimage sensing device in response to the read command.
 22. The image datatransmission method as claimed in claim 13, further comprising: when thefirst data sequence is ready, transmitting an interrupt signal to themaster device by the image sensing device, such that the master devicetransmits the read command to the image sensing device in response tothe interrupt signal.
 23. The image data transmission method as claimedin claim 13, wherein the image sensing device further comprises adetermination pin, and the image data transmission method furthercomprises: when the first data sequence is ready, driving a potential ofthe determination pin to a specific potential by the image sensingdevice, such that the master device transmits the read command to theimage sensing device after detecting that the potential of thedetermination pin is the specific potential.